You have a server named Server1 that runs Windows Server 2008. The server has the Web Server （IIS） server role installed.  You have an SMTP gateway that connects to the Internet. The internal firewall prevents all computers， except the SMTP gateway， from establishing connections over TCP port 25. You configure the SMTP gateway to relay e-mail for Server1.  You need to configure a Web site on Server1 to send e-mail to Internet users. What should you do？（）

• A、On Server1， install the SMTP Server feature.
• B、On Server1， configure the SMTP E-mail feature for the Web site.
• C、On an internal DNS server， create an MX record for Server1.
• D、On an internal DNS server， create an MX record for the SMTP gateway.